South African Class 8F 4-8-0
{{Short description|1904 design of steam locomotive}}
{{About|one of several different Cape Government Railways locomotive types to be designated "8th Class"|the others|Cape Government Railways 8th Class locomotives}}
{{Use dmy dates|date=December 2013}}
{{Use South African English|date=December 2013}}
{{Infobox locomotive
| name = CGR 8th Class 4-8-0 1904
South African Classes 8F & 8FW 4-8-0
| image = Class 8FW 1236 (4-8-0).JPG
| alt =
| caption = Class 8FW no. 1236 plinthed at De Aar, 27 May 2013
| hatnote = ♠ Original locomotive, as built
{{font color|red|♥}} Superheated, inside admission valves, Class 8FW
| powertype = Steam
| designer = Cape Government Railways
(H.M. Beatty)
| builder = North British Locomotive Company
| ordernumber =
| serialnumber = 16161-16170
| buildmodel = CGR 8th Class (4-8-0)
| builddate = 1904
| totalproduction = 10
| rebuilder =
| rebuilddate =
| numberrebuilt =
| whytetype = 4-8-0 (Mastodon)
| uicclass = ♠ 2'Dn2 - {{font color|red|♥}} 2'Dh2
| driver = 2nd coupled axle
| gauge = {{Track gauge|Cape|allk=on}}
| leadingdiameter = {{convert|28+1/2|in|mm|0|abbr=on}}
| coupleddiameter = {{convert|48|in|mm|0|abbr=on}}
| trailingdiameter =
| tenderdiameter = {{convert|33+1/2|in|mm|0|abbr=on}} as built
{{convert|34|in|mm|0|abbr=on}} retyred
| minimumcurve =
| wheelbase = {{convert|46|ft|10+1/2|in|mm|0|abbr=on}}
| engine total = {{convert|23|ft|3|in|mm|0|abbr=on}}
| leading = {{convert|6|ft|mm|0|abbr=on}}
| coupled = {{convert|13|ft|6|in|mm|0|abbr=on}}
| trailing =
| tender total = {{convert|14|ft|7|in|mm|0|abbr=on}}
| tenderbogie = {{convert|4|ft|7|in|mm|0|abbr=on}}
| pivotcentres =
| wheelspacing =
| length =
| over couplers = {{convert|54|ft|2+1/4|in|mm|0|abbr=on}}
| over bufferbeams=
| width =
| height = ♠{{font color|red|♥}} {{convert|12|ft|10|in|mm|0|abbr=on}}
| frametype = Bar
| axleload = ♠ {{convert|11|lt|14|lcwt|kg|sigfig=4|abbr=on}}
{{font color|red|♥}} {{convert|12|lt|11|lcwt|kg|sigfig=4|abbr=on}}
| leadingbogie/pony= ♠ {{convert|12|lt|9|lcwt|kg|sigfig=4|abbr=on}}
{{font color|red|♥}} {{convert|12|lt|15|lcwt|kg|sigfig=4|abbr=on}}
| coupled all = ♠ {{convert|11|lt|14|lcwt|kg|sigfig=4|abbr=on}}
| coupled 1 = {{font color|red|♥}} {{convert|11|lt|18|lcwt|kg|sigfig=4|abbr=on}}
| coupled 2 = {{font color|red|♥}} {{convert|12|lt|11|lcwt|kg|sigfig=4|abbr=on}}
| coupled 3 = {{font color|red|♥}} {{convert|11|lt|19|lcwt|kg|sigfig=4|abbr=on}}
| coupled 4 = {{font color|red|♥}} {{convert|11|lt|18|lcwt|kg|sigfig=4|abbr=on}}
| coupled 5 =
| coupled 6 =
| coupled 7 =
| coupled 8 =
| trail bogie/pony=
| tenderbogieload = Bogie 1: {{convert|20|lt|14|lcwt|kg|sigfig=4|abbr=on}}
Bogie 2: {{convert|22|lt|7|lcwt|kg|sigfig=4|abbr=on}}
| tenderaxle = {{convert|11|lt|3|lcwt|2|qtr|kg|sigfig=4|abbr=on}}
| weightondrivers = ♠ {{convert|46|lt|16|lcwt|kg|sigfig=4|abbr=on}}
{{font color|red|♥}} {{convert|48|lt|6|lcwt|kg|sigfig=4|abbr=on}}
| locoweight = ♠ {{convert|59|lt|5|lcwt|kg|sigfig=4|abbr=on}}
{{font color|red|♥}} {{convert|61|lt|1|lcwt|kg|sigfig=4|abbr=on}}
| tenderweight = {{convert|43|lt|1|lcwt|kg|sigfig=4|abbr=on}}
| locotenderweight = ♠ {{convert|102|lt|6|lcwt|kg|sigfig=4|abbr=on}}
{{font color|red|♥}} {{convert|104|lt|2|lcwt|kg|sigfig=4|abbr=on}}
| tendertype = XF (2-axle bogies)
XC, XC1, XD, XE, XE1, XF, XF1, XF2, XJ, XM, XM1, XM2, XM3 permitted
| fueltype = Coal
| fuelcap = {{convert|10|lt|t|1|abbr=on}}
| watercap = {{convert|3000|impgal|L|sigfig=3|abbr=on}}
| tendercap =
| sandcap =
| fireboxtype = Round-top
| firearea = ♠ {{convert|21.35|sqft|m2|abbr=on}}
{{font color|red|♥}} {{convert|21|sqft|m2|abbr=on}}
| boiler =
| boilertype =
| pitch = ♠{{font color|red|♥}} {{convert|7|ft|3|in|mm|0|abbr=on}}
| diameterinside = ♠{{font color|red|♥}} {{convert|5|ft|mm|0|abbr=on}}
| lengthinside = ♠ {{convert|11|ft|1/4|in|mm|0|abbr=on}}
{{font color|red|♥}} {{convert|11|ft|3/8|in|mm|0|abbr=on}}
| smalltubediameter= ♠ 205: {{convert|2|in|mm|0|abbr=on}}
{{font color|red|♥}} 115: {{convert|2|in|mm|0|abbr=on}}
| largetubediameter= {{font color|red|♥}} 18: {{convert|5+1/2|in|mm|0|abbr=on}}
| boilerpressure = ♠{{font color|red|♥}} {{convert|180|psi|kPa|0|abbr=on}}
| safetyvalvetype = Ramsbottom
| feedwaterheater =
| totalsurface = ♠ {{convert|1320.6|sqft|m2|abbr=on}}
{{font color|red|♥}} {{convert|1081|sqft|m2|abbr=on}}
| tubearea = ♠ {{convert|1184|sqft|m2|abbr=on}}
{{font color|red|♥}} {{convert|950|sqft|m2|abbr=on}}
| fluearea =
| tubesandflues =
| fireboxarea = ♠ {{convert|136.6|sqft|m2|abbr=on}}
{{font color|red|♥}} {{convert|131|sqft|m2|abbr=on}}
| superheatertype =
| superheaterarea = {{font color|red|♥}} {{convert|214|sqft|m2|abbr=on}}
| cylindercount = Two
| cylindersize = ♠ {{convert|18+1/2|in|mm|0|abbr=on}} bore
{{font color|red|♥}} {{convert|20|in|mm|0|abbr=on}} bore
♠{{font color|red|♥}} {{convert|24|in|mm|0|abbr=on}} stroke
| frontcylindersize=
| rearcylindersize =
| hpcylindersize =
| lpcylindersize =
| valvegear = Stephenson
| valvetype = ♠ Slide - {{font color|red|♥}} Piston
| valvetravel =
| valvelap =
| valvelead =
| transmission =
| trainheating =
| locobrakes =
| trainbrakes =
| safety =
| coupling = Johnston link-and-pin
AAR knuckle (1930s)
| maxspeed =
| poweroutput =
| tractiveeffort = ♠ {{convert|23110|lbf|kN|abbr=on}} @ 75%
{{font color|red|♥}} {{convert|27000|lbf|kN|abbr=on}} @ 75%
| factorofadhesion =
| locobrakeforce =
| operator = Cape Government Railways
South African Railways
| operatorclass = CGR 8th Class
SAR Classes 8F & 8FW
| powerclass =
| numinclass = 10
| fleetnumbers = CGR 829-838
SAR 1234-1243
| officialname =
| nicknames =
| axleloadclass =
| locale =
| deliverydate = 1904
| firstrundate = 1904
| lastrundate =
| withdrawndate = 1972
| preservedunits =
| restoredate =
| scrapdate =
| currentowner =
| disposition =
| notes = The leading coupled axle had flangeless wheels
}}
The South African Railways Class 8F 4-8-0 of 1904 was a steam locomotive from the pre-Union era in the Cape of Good Hope.
In 1904, the Cape Government Railways placed its final batch of ten 8th Class 4-8-0 Mastodon type steam locomotives in service. In 1912, when they were assimilated into the South African Railways, they were renumbered and designated Class 8F.{{Holland-Vol 1|page=67}}{{Paxton-Bourne|pages=48-49}}Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer’s Office, Pretoria, January 1912, pp. 9, 12, 15, 43 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
Manufacture
=Evolution=
The first 8th Class locomotive of the Cape Government Railways (CGR) was a {{nowrap|2-8-0}} Consolidation type designed by H.M. Beatty, the CGR's Chief Locomotive Superintendent from 1896 to 1910. It was later to become the Class 8X on the South African Railways (SAR). While these first Schenectady- and ALCO-built {{nowrap|2-8-0}} locomotives were being subjected to exhaustive testing on all types of traffic and under varying conditions, some trouble was experienced with the leading two-wheeled pony truck. When designs were prepared at Salt River for a later order for more locomotives, the pony truck was replaced with a four-wheeled bogie.
=Builders=
Orders for the last 8th Class locomotives for the CGR were placed with the North British Locomotive Company (NBL) in 1903. The ten locomotives were built and delivered in 1904, numbered in the range from 829 to 838 and allocated to the Western System of the CGR.North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
File:Class 8FW 1236 Type XF tender plate.jpg
These ten locomotives were the final batch of CGR 8th Class locomotives to be built with a {{nowrap|4-8-0}} Mastodon type wheel arrangement.
They were delivered with Type XF tenders with a coal capacity of {{convert|10|lt|t|1|abbr=off}}, a water capacity of {{convert|3000|impgal|L|abbr=off}} and a maximum axle load of {{convert|11|lt|3|lcwt|2|qtr|kg|sigfig=4|abbr=off}}.South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 3'6" Gauge/Spoorwydte. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. pp. VIII, 45.South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 2'0" & 3'6" Gauge/Spoorwydte, Steam Locomotives/Stoomlokomotiewe. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. pp. VIII, 6a-7a, 20-21, 25, 45.
=Class 8 sub-classes=
When the Union of South Africa was established on 31 May 1910, the three Colonial government railways (CGR, Natal Government Railways and Central South African Railways) were united under a single administration to control and administer the railways, ports and harbours of the Union. Even though the South African Railways and Harbours came into existence in 1910, the actual classification and renumbering of all the rolling stock of the three constituent railways was only implemented with effect from 1 January 1912.The South African Railways - Historical Survey. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.
In 1912, these ten locomotives were renumbered in the range from 1234 to 1243 and designated Class 8F.{{Holland-Vol 2|page=140}}
These locomotives, together with the rest of the CGR's 8th Class {{nowrap|2-8-0}} Consolidations and {{nowrap|4-8-0}} Mastodons and the Classes 8-L1 to 8-L3 {{nowrap|4-8-0}} Mastodon locomotives from the Central South African Railways (CSAR), were grouped into ten different sub-classes by the SAR. The {{nowrap|4-8-0}} locomotives were designated SAR Classes 8 and 8A to 8F and the {{nowrap|2-8-0}} locomotives were designated Classes 8X to 8Z.
Modification
File:Class 8FW 1242 (4-8-0).JPG
During A.G. Watson's term as Chief Mechanical Engineer of the SAR from 1929 to 1936, many of the Classes 8 to 8F locomotives were equipped with superheated boilers, larger bore cylinders and either inside or outside admission piston valves. The outside admission valve locomotives had their cylinder bore increased from {{convert|18+1/2|to|19|in|mm|0|abbr=off}} and retained their existing SAR classifications, while the inside admission valve locomotives had their cylinder bore increased to {{convert|20|in|mm|0|abbr=off}} and were reclassified by having a "W" suffix added to their existing SAR classifications.
Of the Class 8F locomotives, numbers 1236, 1242 and 1243 were equipped with superheated boilers, {{convert|20|in|mm|0|abbr=off}} bore cylinders and inside admission piston valves, and reclassified to Class 8FW.
Service
Preservation
Class 8FW no. 1236 is preserved and plithed at De Aar. It is the sole surviving Class 8F in South Africa.
Illustration
File:SAR Class 8F 1236 (4-8-0) CGR 831.jpg|Ex CGR 8th Class no. 831, SAR Class 8F no. 1236, before modification and reclassification, c. 1930
References
{{Commonscat|South African Class 8F (4-8-0)|South African Class 8F 4-8-0|position=left}}
{{Reflist|30em}}
{{Locomotives of the Cape Government Railways}}
{{Locomotives of South Africa}}
{{Steam locomotive tenders}}
Category:Cape gauge railway locomotives